import os
import pygame

pygame.init()
screen = pygame.display.set_mode([800, 600])

keep_going = True

colorGreen = (0x00, 0xff, 0x00)
pos = (100, 100)
radius = 50

while keep_going:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            keep_going = False
    pygame.draw.circle(screen, colorGreen, pos, radius)
    pygame.display.update()

pygame.quit()